Jervois have killed off any realistic chance of Tailem Bend defending their title with a hard fought, but in the end convincing two rink, 15 shot win over their rivals.
Scores were tight for most of the day, but Jervois finished much stronger over the final stages to clinch the win.
First time skipper Tim Hicks was the biggest winner for the home side, with Schenke, Denis Hicks and Scannell having a nine shot win over Tailems' Schenke, Stevens, McDonald and Ackland.
After a tight start, Hicks strung together six successive ends to take a nine shot lead with a five on the 8th being decisive, but this was gradually reduced to just two shots after 18 ends.
But, with the game in the balance Hicks finished much stronger, adding seven shots to nil, with a four on the 20th sealing the win 23 to 14.
David Kempe has been having a tough time of late, and this looked like continuing when his rink of Vanderzon, Brandle and Tyas were down six shots to nil against Edwards, Hales, Rooke and Baxter, with Edwards causing plenty of problems early.
The home side managed to edge to the lead by the break by a single shot before dropping a four on the 12th, but from then on gained the ascendancy as Tyas found his range and Edwards struggled to maintain his early dominance. Kempe took seven of the last nine ends for a solid 24 to 17 win.
Tailem salvaged two points with a single shot win when Sam Shepherd, Hoare, Tomkinson and Glenda Shepherd held off a fast finishing Herbert, S Hicks, Solley and Fromm.
It was a rare loss for the in form Herbet's rink, but by winning the final four ends against quality opposition they helped ensure the win for the home side and consigned the reigning champs, fielding their strongest side of the season, to almost certain wooden spooners.
Jervois dominated on all rinks over the last five ends, scoring 19 shots to four, which exactly coincided with the eventual winning margin.
Mannum have shored up top position with a 21 shot win over Murray Bridge, opening up a break over the rest of the comp.
Fowler, Leathers, Towns and VanTijn were dominant in a 19 shot win over McIntosh, Leckie, Ferris and Di Santo. They started with a 2, 3 and 2 for an early break, but it was a six on the sixth end that propelled them out to 17 to 3 lead after nine ends.
Things never improved much from there for the visitors with the margin continuing to extend apart from a brief period either side of the break.
McDonnell, Wegener, Newman and Dicker scored an 8 shot win over Attrill, Shilton, Gill and Penta, a relatively narrow margin given they won 15 ends to 6.
The first five ends went McDonnells way as he took an eight nil lead, and from there Attrill could not get within five shots.
The damage could have been much worse as Macca won six singles over the final seven ends, but dropped a five on the other to hardly better than break even over the run home.
Ben Traeger finally broke through for a win with Paul Smart and Tony and Les Trewren over Mannum's Wakefield, Howe, Windebank and Mundie by six shots.
The scores were tied at eight all at the break, but Traeger took five ends in a row upon the resumption to gain a matchwinning 10 shot lead which saw them safely home.
Karoonda scored a vital three shot away win over RSL, creating a logjam for the second to fifth placed sides who are all separated by less than a win.
I Symonds, S Wood, Jones and Cornish were 12 shot winners over K Kneebone, Bolt, A Kuchel and Wooldridge.
Symonds was off to a flyer, leading 14 to 1 after 8 ends, but failed to maintain the dominance from thereon. The win was never in doubt, but with the scores tight overall he would be a little disappointed not to register a bigger win.
R Zadow, Tomkinson, L Symonds and G Zadow dominated most of their match against N Kneebone, Little, Thiele and Daniel, but had to settle for a two shot win.
Six winning ends in a row to Zadow leading up to the break had him leading by 10 shots, but a four and single to Kneebone halved the margin after the break.
Zadow steadied with four successive singles and seemingly had the game safely in hand with four ends to go.
A single to Kneebone was followed by a six and suddenly there was only two shots difference with two ends to go.
Zadow responded with a two, but dropped two on the last, hanging on for a two shot win.
Sipos, Bristow, Walker and Kennedy kept RSL in the hunt with a great start over Waechter, Porker, Kroehn and Wegner, but also let their lead slip before finishing strongly to win by 11 shots.
Sipos had the first nine shots on the board in winning the first five ends, but led by just a single shot at the break.
From there on Sipos conceded just 3 singles while adding another 13 shots in the 23 to 12 win.